1. Field of the Invention
This invention relates to a biochemical analysis apparatus for applying a liquid sample to a test film provided with a single reagent layer or a plurality of reagent layers, maintaining the test film at a predetermined temperature (i.e. carrying out incubation) for a predetermined time, and measuring the degree of reaction of the reagent with the liquid sample during or after the incubation.
2. Description of the Prior Art
Qualitative or quantitative analysis of a specific chemical constituent in a liquid sample is generally conducted for various industrial purposes. Particularly, it is very important in biochemical and clinical fields to quantitatively analyze chemical constituents or physical constituents in body fluid such as blood or urine.
In recent years, as disclosed in, for example, Japanese Patent Publication No. 53(1978)-21677 and Japanese Unexamined Patent Publication No. 55(1980)-164356, there has been developed and put into practice a dry type chemical analysis slide for quantitatively analyzing a specific chemical constituent or a specific physical constituent contained in a liquid sample simply by applying a droplet of the liquid sample. With the chemical analysis slide, it is possible to analyze a liquid sample more simply and more quickly than with the conventional wet type analysis method. Therefore, the use of the chemical analysis slide is desirable particularly in medical organizations, research laboratories, or the like where many samples are to be analyzed.
In order to quantitatively analyze a chemical constituent or the like contained in a liquid sample by use of the chemical analysis slide, a measured amount of the liquid sample is put on the chemical analysis slide and is maintained at a predetermined temperature (i.e. incubated) for a predetermined time in an incubator to cause a color reaction. The chemical analysis slide is then exposed to measuring light having a wavelength selected in advance in accordance with the combination of the constituent of the liquid sample with a reagent contained in the reagent layer of the chemical analysis slide, and the light reflected by the chemical analysis slide is measured in terms of the optical density.
Also, it has heretofore been known to quantitatively analyze ionic activity in a liquid sample by use of an electrolyte determination slide. In this case, analysis is carried out by applying the liquid sample and a reference solution to the slide, incubating the slide, and then measuring a difference in potential corresponding to the difference in ionic activity between the liquid sample and the reference solution.
In the medical organizations, research laboratories or the like in which many liquid samples are to be analyzed, it is desirable that the analysis be conducted automatically and sequentially. To satisfy this need, there have been proposed various chemical analysis apparatuses for carrying out sample analysis automatically and sequentially by use of the aforesaid chemical analysis slides. One of such chemical analysis apparatuses is disclosed in, for example, Japanese Unexamined Patent Publication No. 56(1981)-77746. Also, as a means for analyzing liquid samples automatically and sequentially, there has been proposed in, for example, U.S. Pat. No. 3,526,480 an apparatus wherein a long tape-like test film containing a reagent is used instead of the aforesaid chemical analysis slides, and sample application, incubation and measurement are carried out sequentially by pulling out the test film.
With the aforesaid conventional techniques, the electrolyte determination slides or the chemical analysis slides are used, or the long tape-like test film is used instead of the chemical analysis slides. (In this specification, the electrolyte determination slide, the chemical analysis slide and the long tape-like test film are generically referred to as the test film.) The liquid sample is applied onto the test film, the sample-applied test film is conveyed into the incubator, and the test film incubated for a predetermined time is conveyed to a measurement means and subjected to measurement. Therefore, in the case where the conveyance accuracy is low, the measurement accuracy deteriorates as the sample applying position on the test film deviates from predetermined position, the incubation accuracy becomes low or a portion slightly deviated from the sample-applied portion of the test film is measured.